A suicide bomber detonated an explosive Friday in front of the U.S. Embassy in Ankara, killing himself and a Turkish guard in an attack that Turkish officials blamed on domestic leftists.Turkey and the U.S. immediately condemned the attack and U.S. officials urged Americans to stay away from all U.S. diplomatic offices throughout Turkey.

A Turkish woman was also seriously wounded and two other guards sustained lighter wounds in the 1:15 p.m. blast in the Turkish capital, Interior Minister Muammer Guler told reporters.

There was no immediate claim of responsibility, but Guler said "preliminary information" obtained by police indicated that the bomber was likely connected to a domestic left-wing militant group. He did not elaborate.

A police official, meanwhile, told The Associated Press that the bomber is most likely a suspected member of the outlawed Revolutionary People's Liberation Party-Front, or DHKP-C. He spoke on condition of anonymity because he was not permitted to speak to the press.

The group has been designated a terrorist organization by the United States but had been relatively quiet in recent years.

Friday's explosion occurred inside the security checkpoint at the side entrance to the U.S. embassy, which is used by staff. A guard standing outside the checkpoint was killed while the two guards that were wounded "were standing in a more protected area," Guler said.

Police and ambulances swarmed the area and authorities immediately cordoned it off. Forensic investigators in white outfits and gloves combed the site.

TV footage showed the embassy door blown off its hinges. The blast also shattered the windows of nearby businesses, littering debris on the ground and across the road. The inside of the embassy did not appear to be damaged.

Television footage also showed what appeared to be a U.S. marksman in a helmet and body armor surveying the area from the roof of an embassy building.

The U.S. Embassy building in Ankara is heavily protected and located near several other embassies, including that of Germany and France. The Hurriyet newspaper said staff at the embassy took shelter in "safe room" inside the compound soon after the explosion.

In a statement, the U.S. Embassy thanked Turkey for "its solidarity and outrage over the incident."

U.S. Ambassador Francis Ricciardone declared that the U.S. and Turkey "will continue to fight terrorism together" and described the U.S. Embassy compound as secure.

"From today's event, it is clear that we both suffer from this terrible, terrible problem of today's world. We are determined after events like this even more to cooperate together until we defeat this problem together," he said.

Turkish Prime Minister Recep Tayyip Erdogan echoed that sentiment, saying the attack aimed to disturb Turkey's "peace and prosperity" and demonstrated a need for international cooperation against terrorism.